Influence of dynamic LED irradiation mode on the content of nitrates, structural and functional characteristics of lettuce plants

One of the promising irradiation modes for plant is dynamic, when parameters change throughout the growing process depending on certain factors. In this work, lettuce plants were illuminated under different LED light sources, including white (2700 K), 30% white (2700 K) + 70% red (660 nm), 15% blue (445 nm) + 85% red (660 nm), 40% blue (445 nm) + 20% red (630 nm) + 40% red (660 nm) and dynamic mode for 35 days to investigate the effects. Photosynthetically active flux density was the same for all lettuce samples during the experiment (210 µmol m −2 s −1 ). The results showed the effects of photoregulation on the growth and development of lettuce plants. Optimal irradiation regime for lettuce plants was a dynamic regime formed using two colour components: white (2700 K) and red (660 nm) LEDs. Lettuce grown under dynamic conditions had a lower content of nitrates and developed faster than under stationary conditions.